Deinsulator for electric conductors



W 9 c. M. DEAVER DEINSULATOR FOR ELECTRIC CONDUCTORS Filed June 13, 1954 INVENTOR Cyril M. flew/er,

w ATTORNEYS UNITED STATES PATENT OFFICE DEINSULATOR FOR ELECTRIC CONDUCTORS Cyril M. Deavcr,

Terre Haute, Ind.

Application June 13, 1934, Serial No. 730,423

3 Claims.

The object of my invention is to produce an eificient tool for removing an intermediate portion of insulation from an insulated electrical conductor, the construction being such that re- 5 mo-val may be accomplished rapidly and efiiciently without injury to the conductor.

The accompanying drawing illustrates my invention:

Fig. 1 is a side elevation on an exaggerated scale, of one of the two mating jaws of my tool;

Fig. 2 is a side elevation of the mating jaw;

Figs. 3 and 4 are respectively elevations of the mating faces of the jaws shown in Figs. 1 and 2;

Figs. 5 and 6 are end elevations respectively of said jaws;

Figs. 7 and 8 are respectively transverse sections on the lines 'I'I of Fig. l and-88 of Fig. 2;

Figs. 9 and 10 are sections, similar to Figs. 7 and 8, of a modification especially desirable for operation upon paper insulated wires;

Fig. 11 is an elevation, on a reduced scale, of my tool associated with pliers of a well known form; and

Fig. 12 is an elevation of another well known form of pliers equipped with my tool.

In the drawing, I indicates a main bar having along one side a cutting or insulation-penetration ridge II. Near, or at, each end bar II] is provided with two pairs of cutter fingers I2, I2 and I3, I 3, the fingers of each pair being laterally separated to form, adjacent ridge II, a wire receiving crotch I4. The tips and crotch edges of the fingers I2 and I3 are reduced to cutting or semi-cutting edges, as indicated at I5, which extend preferably to the roots of the fingers adjacent the ridge I I.

The other jaw of my tool is similar in construction, comprising a main bar I6 with cutter finger pairs IT, I! and I8, I8, forming crotches 20 and the main bar having a ridged inner edge I9. The cutting edges 2| of finger pairs I! and I8 are at the outer faces of the fingers, and the cutting edges I at the inner faces of fingers I2 and I3. The finger pairs I'I-I8 are spaced apart, longitudinally of the bar I6, a distance equal to the distance between the inner faces of the finger pairs I2 and I3.

The bar I6 preferably projects at its ends beyond the cutting faces of the finger pairs I1 and I8 and the ridge II of bar III is preferably continued at least to the outer faces of the fingers I2 and I3 so that the length of ridge II is substantially equal to the length of ridge I9. As

previously described, the inner faces of fingers I2 and I 3 respectively coact with the outer faces of fingers I1 and I8 and extension of the ridges II and I9 beyond these coacting planes provides supports for the portions of the wire immediately adjacent the region from which the insulation is being removed, said supports penetrating the insulation and preventing cocking of the wire immediately adjacent the removal planes.

I have found that, in operating upon paper insulated wires, especially of the smaller sizes such as are used in telephony, there is a tendency for the ridges II and B9 to slip sidewise on the insulation so that they do not properly penetrate to the wire, and that this difficulty may be avoided, as shown in Figs. 9 and 10 by forming a shallow groove 30 longitudinally and medially of the crest of the ridge.

It will be readily understood that a mating pair of jaws such as I have described may be manipulated by any desired means. In Fig. 11 I have indicated a mounting of these jaws upon the coacting parallel motion jaws 35, 35 of a well known form of pliers.

In Fig. 12 I show a pair of these jaws between the hand ends of the levers 36 of another well known form of pliers commonly used by telephone installers. It will be noted that these stripping jaws move toward and from each other in a plane at right angles to the ridges I I and I9 and, as the wire receiving crotches are eased out at their mouths, the stripping jaws may be moved toward and from each other around any axis which is parallel to the ridges.

While it is preferable that the fingers I2, I3, I! and I8 be comparatively thin in their dimension parallel with the ridges H and I9, as indicated in the drawing, this dimension of these fingers may nevertheless be quite considerable without interferring with efficiency of insulation removal, although there should preferably be a substantial gap between the fingers II and I8.

In use the jaws are placed upon opposite sides of an insulated wire, at the point of desired insulation removal, in the mouths of the several crotches, and forced together upon the wire. The several fingers penetrate the insulation to, or nearly to the wire and the crests of the two ridges also penetrate or compress the insulation. The pressure produced by the ridges bursts the insulation between the two finger-penetration planes and the coacting fingers sever the insulation at two separated planes. When the jaws are withdrawn the insulation between the two fingerpenetration planes may be easily picked out by the operator.

While I prefer that the penetration fingers of one jaw be so spaced as to lie between the penetration fingers of the coacting jaw it will be readily understood that other spacing of said fingers which will permit intimate interdigitation of the fingers or" one jaw with the fingers of the coacting jaw may be provided without departing from my invention.

If the dimension of the fingers parallel with the ridge is sufiiciently small, sharpening of the crotch edges is not necessary for many types of insulation.

I claim as my invention:

1. An insulation-stripping tool comprising a pair of coacting jaws each having a ridge-like portion, placeable longitudinally of an insulated wire, and a pair of insulation-entering fingers on opposite sides of the ridge and projecting laterally beyond the crest of said ridge to form a wirereceiving crotch, said fingers having sharpened crotch edges at one face of the fingers, the fingers of one ridge portion being spaced longitudinally thereof, and the fingers of the other ridge portion being spaced longitudinally thereof to engage the outer surfaces of said first fingers, said first ridge portion being extended longitudinally beyond said outer surfaces of its fingers.

2. An insulation-stripping tool comprising a pair of coacting jaws each having a ridge-like portion, placeable longitudinally of an insulated wire, and a pair of insulation-entering fingers on opposite sides of the ridge and projecting laterally beyond the crest of said ridge to form a wirereceiving crotch, the crest of at least one of said ridge-like portions being transversely concaved.

3. An insulation-stripping tool comprising a pair of coacting jaws each having a ridge-like portion, placeable longitudinally of an insulated wire, and a pair of insulation-entering fingers on opposite sides of the ridge and projecting laterally beyond the crest of said ridge to form a wire-receiving crotch, the crest of each ridge being located at the base of its associated crotch and entirely without the area embraced in said crotch, the crest of at least one ridge being transversely concaved.

CYRIL M. DEAVER.

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